Alicia Ault

June 08, 2016

NATIONAL HARBOR, Maryland — Regular walking on a treadmill may improve cognitive abilities and physical fitness in ambulatory patients with relapsing-remitting multiple sclerosis (MS), a small pilot study shows.

Cognitive impairment is a common disability, affecting at least half of those with MS, but there is no US Food and Drug Administration–approved treatment specifically for cognitive difficulties in MS.

Exercise has been shown in various studies to help prevent or lessen cognitive symptoms in other illnesses, but five randomized controlled trials of exercise training and cognition in MS have not been as positive, said Brian M. Sandroff, PhD, associate research scientist at the Kessler Foundation, West Orange, New Jersey, at the Consortium of Multiple Sclerosis Centers (CMSC) 2016 Annual Meeting.

Dr Sandroff said those studies had methodologic concerns — for instance, not focusing on cognition as a primary outcome. He and colleagues at Kessler and the University of Illinois at Urbana-Champaign, Urbana, decided to design a pilot trial that would provide proof of concept that a long-term exercise program could be an optimal intervention to improve cognitive processing speed and executive function.

After 3 days of treadmill walking a week over 12 weeks, the five patients who received the intervention had improvements in cognitive measures, cardiorespiratory fitness, and walking, as measured by the 6-minute walk test, Dr Sandroff told Medscape Medical News.

The intervention is ideal for "people who don't use an assistance device to walk, but who are also demonstrating signs of cognitive impairment," he said. A few of the patients had a score of 4 on the Expanded Disability Status Scale (EDSS), which made it scary when they first got on the treadmill, he said. But, "by the end, they were walking like champs," Dr Sandroff said.

Robert Lisak, MD, president of the Consortium of Multiple Sclerosis Centers, called the results "intriguing," especially because there are no drugs to improve cognition or fatigue. But it's not clear how such an exercise program could work in someone who's not particularly mobile, Dr Lisak told Medscape Medical News.

Researchers still need to answer other questions, he said. "Do you have to continue using that treadmill after you're done with the 6-week course, and do you have to do it as intensively, or just something is better than nothing?"

The basic question is, "How long do these effects last, especially if you go back home and just do the minimum or none?" said Dr Lisak, Parker Webber Chair in Neurology at Wayne State University School of Medicine, Detroit, Michigan.

Dr Sandroff said that he and his colleagues will be examining the maintenance of effect in a large randomized, controlled trial in patients with MS who have impaired cognition. The National Institutes of Health will fund the study, he said.

Pilot Results

In the pilot, five women with relapsing-remitting MS were randomly assigned to the 12-week exercise intervention, while another five women, also with relapsing-remitting MS, were put on a wait list for the intervention.

The mean ages were 41 to 44 years, the women had had their disease for 12 years, and the EDSS ranged from 1.5 to 4. Before starting the trial, all 10 patients underwent a battery of cognitive tests, including the Symbol Digit Modalities Test (SDMT) to measure cognitive processing speed, the Delis–Kaplan Executive Function System Sorting Test, and the Modified Flanker Test. Cardiorespiratory fitness was measured with VO2 peak.

Exercise participants started out with light walking for 15 to 20 minutes in each session. By the end of the 12 weeks, they had worked their way up to 30 to 40 minutes of vigorous walking per session. Participants attended 96% of the sessions, said Dr Sandroff.

Cognitive and fitness measures were taken again at the conclusion of the study. The biggest improvement was in the women who walked. They saw a 3-point gain in their SDMT score, compared with an almost 4-point decline for the nonwalkers. None of the other cognitive measures improved.

Walkers also increased their VO2 max (d = 1.08), while nonwalkers experienced a slight decline.

The study wasn't powered to detect a statistically significant difference between the two groups, said Dr Sandroff. But, he said, the changes in VO2 peak were significantly associated with changes in SDMT scores, indicating that improved cardiorespiratory fitness was moderately to strongly associated with improvements in cognitive processing speed.

Dr Sandroff and Dr Lisak have disclosed no relevant financial relationships.

Consortium of Multiple Sclerosis Centers (CMSC) 2016 Annual Meeting: Whitaker Research Track, Session I. Presented June 3, 2016.

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